The masticatory movements of the mandible of humans are normally rhythmic, automatic and powerful. Coordination of tongue movements with the masticating motion of the mandible is necessary and automatic in the normal chewing cycle. However, injury or alteration of the cerebral cortex, the reticular or pyramidal systems, the trigeminal nucleus or the hypothalamus can result in uncoordinated glossal movements in the comatose state of an individual. The comatose patient often exhibits powerful (300 psi) ruminatory reflex chewing patterns which are extremely difficult to control and frequently result in severe self-inflicted trauma to the soft tissues of the oral cavity, particularly the tongue. This often allows the tongue or cheek to become juxtapositioned between the teeth and this further aggravates the chewing reflex in the decerebrate state with extremely damaging results.
Several oral appliances have been used in attempts to prevent oral damage by the patient. These include intermaxillary fixation using arch wires in combination with hard acrylic devices. Also, hard rubber or plastic mouth props, plastic airways and flexible or inflexible bite splints over the occlusal surfaces of the teeth have been used. Typical of the appliances of the prior art are described in U.S. Pat. Nos. 1,466,559, issued to C. G. Purdy on Aug. 28, 1923; 2,694,397, issued to F. W. Herms on Nov. 16, 1954; 3,307,539, issued to G. A. Peterson on Mar. 7, 1967; and 4,041,937, issued to M. Diaz on Aug. 16, 1977. Other work in this field appears in the following publications: "A Tongue Stent for Prevention of Oral Trauma in the Comatose Patient", G. E. Hanson, et al., Critical Care Medicine, Vol. 3, No. 5, p. 200 (1975); "The Use of Tongue-Depressing Stents for Neuropathologic Chewing", M. J. Jackson, Jl. Prosthetic Dentistry, Vol. 40, No. 3, p. 309 (1978); "An Occlusal Prosthesis to Assure Airway Patency in the Comatose Patient", W. A. Levine, et al., Jl. Prosthetic Dentistry, Vol. 44, No. 4, p. 451 (1980); and "Prevention of Self-Inflicted Trauma in Comatose Patients", T. E. D. Peters, et al., Oral Surgery, Vol. 57, No. 4, p. 367 (1980).
Many of the prior art appliances have been found to actually worsen an already severe problem. If the wire or rigid plastic components break they create jagged, virtually non-detectable foreign bodies which may be aspirated into the lungs. These may also lacerate the throat, larynx or soft tissue of the oral cavity. The non-flexible nature of these appliances often cause fractures of the occlusal and incisal surfaces of the teeth, especially if the teeth have been restored with amalgam or composite material. The fractured filling material and tooth fragments also become foreign bodies. Exposure of vital pulp tissue is common in tooth fracture situations creating even further complications.
Many of the prior devices require the use of impressions or molds to obtain positional relationships of the teeth. For patients of the type having involuntary mandible motions, these impressions must be made while the patient is under heavy sedation or general anesthesia. Some appliances can only be inserted under such sedated conditions. The sedation of a comatose patient is always dangerous. Further, materials used in making the impression introduce problems similar to those generated by breakage of the appliance itself during use.
The comatose state of a patient can be relatively short, as after surgery under a general anesthesia, or very extended due to an accident, stroke or the like. For extended comatose times, frequent oral hygiene steps and periodic oral examination are desirable; however, the appliances of the prior art generally prevent such actions. Often the care of long-term comatose patients is the responsibility of a family member. As such, the family member is unable to cope with problems generated by the appliances of the prior art. Furthermore, just as turning of a patient in bed to prevent bedsores and stiffness is desirable, a periodic change of appliance position is desirable to prevent chronic soreness and cutting of the mouth. This is not possible with the prosthesis units known in the art.
Accordingly, it is an object of the present invention to provide a simple oral appliance to prevent damage to the teeth or surrounding soft tissue of a comatose patient or the like.
It is another object to provide an oral injury prevention device that is resilient and flexible, with properties to withstand extreme and prolonged biting force without becoming fragmented or perforated.
An additional object is to provide an oral appliance for use with a comatose patient that does not interfere with normal mandibular movements, such as yawning and lateral movements, and permits regular oral hygiene and oral examination.
A further object is to provide an oral appliance that does not require the making of impressions or the use of any special sedation for installation, removal, or maintenance.
It is also an object of the present invention to provide an oral appliance for use with comatose patients and the like that can be easily switched from side-to-side by either medically skilled or unskilled attendants of the patient.
These and other objects of the present invention will become apparent upon a consideration of the drawings of the invention when reviewed in light of the detailed description that follows.